The current power-driving method of LCD panel is that the alternating-current power output by the alternating power source is converted by an AC/DC power supply into the low-voltage direct-current power, wherein the present specification of the direct-current low-voltage power adopted by various manufacturers includes 5V, 12V, 24V, 48V, etc. The low-voltage direct-current power is provided for the low-voltage loads of the display panel, including driver circuit of the display panel, image-processing circuit board, speakers, etc. The low-voltage direct-current power is also shunted to a high-voltage power converter system, and the high-voltage power converter system boosts the low-voltage direct-current power to output a high-voltage power to drive the high-voltage load of the display panel, which is the display panel's backlight module having gas-discharge lamps, such as cold cathode fluorescent lamps.
With the uprising of environmental protection, the design of power driver circuit has to meet the demand of promoting the power factor or power efficiency in order to achieve the objective of energy saving. A lower-voltage power converter system also has a power-factor corrector to reduce power consumption. The size of LCD panel is growing larger and larger, especially that of LCD TV, and thus, the driving power for high-voltage loads is also growing higher responsively. The conventional power source of the high-voltage power converter system comes from the lower-voltage direct-current power output by the lower-voltage power converter system; thus, the larger-size LCD TVs, such as 32 inch or 40 inch, need larger lower-voltage power converter system to output higher power. The specification of active power-factor corrector is growing more and more complex and becomes hard to fabricate. Further, the conventional power-factor corrector is based on the capacitive charge or discharge, which results in that when the display panel is switched off, the low-voltage power converter system, which is normally electrically coupled to the alternating power source, will still consume a given amount of electrical power, and it will not meet the severe electrical-power standard of environmental protection, such as power consumed in standing-by less than 1 W.